Validation of accuracy in navigation systems

System validation of accuracy is an offline procedure performed periodically to confirm that the tracking system is accurate. In some cases, validation of accuracy can be performed as an ASTM (American Society for Testing and Materials) testing procedure.

The testing involves a standard jig assembly, used to pick standard locations. The validation system makes sure that each location is yielding a coordinate within some tolerance from the standard.

The objectives of this validation are two:

First, to ensure that the tracking system’s accuracy complies with FDA standards.

Second, to maintain this level of accuracy during the system life cycle.

Validation of Accuracy – Procedure

Validation of accuracy is performed using a standard (ASTM) jig. This jig contains a set of locations with their X, Y and Z values. In addition, the jig contains a marker, whose function is to log the jig’s location in the world. During the testing process, the surgery tool is moved between the jig points at some standard sequence. It is parked at each jig point for a short duration, though long enough to let the system record its location. The ASTM software calculates the X, Y Z location relative to the first (“world”) location. Each coordinate is then validated to be within the ASTM tolerance from the corresponding reference point.

Additional testing checks the location accuracy in cases where the tool is held diagonal to the jig’s surface at a few reference angles. This test ensures that accuracy is maintained for various working orientations.